Wi-Fi on a Boat
Making shore-based Wi-Fi Internet work well on a boat. __FORCETOC__ Common Problems In locations where shore-based Wi-Fi signals are strong, using them for Internet on a boat is comparable to using Wi-Fi hotspots on land. However, the marine environment tends to exacerbate general Wi-Fi problems and create problems of its own: * Boat hulls and sailboat masts can block the radio signal, reducing range. * Movement of other boats can cause temporary interruptions of Wi-Fi connections. * Location of the Wi-Fi antenna in a cabin below deck can further reduce range. * It may be difficult or impossible to get close enough to the Wi-Fi access point for sufficient signal, especially when anchored. * Boat movement can result in aiming problems with highly directional antennas. * Moisture in the marine environment can result in electronic failures. Improving Wi-Fi Higher Power While it may seem that higher power Wi-Fi might help to improve your range, that's not necessarily true, since higher power only helps on transmit, not receive. Thus it's only likely to help if the other end of your connection is using higher power as well, which is often not the case. In other words, what you may well wind up with is an alligator, big mouth but small ears. Also, unnecessarily high transmit power will tend to increase your interference with other Wi-Fi users, making you a bad neighbor. It's usually much better to just improve your antenna, which helps both transmit and receive. Better Antenna Usually the best way to improve range is to use a better antenna (or reflector with a standard antenna), which helps both transmit and receive. Better antennas work by being directional: * concentrating radio energy/sensitivity to/from the desired direction instead of wasting it in other directions, and * reducing interference from other radio sources not in the desired direction (path). The improvement in antenna performance is referred to as gain, where a higher number indicates the amount of performance improvement expressed in dBi. It takes an increase of 3 dBi to double range; e.g., as compared to a typical 2 dBi antenna: * 5 dBi antenna has double the range * 8 dBi antenna has 4 times the range However, a highly directional antenna can be problematic on a boat, since it must be kept aimed accurately at the remote end of the connection, which can be difficult on a boat floating in the water (even when tied up). The width (angle) of the directional pattern (both vertically and horizontally) can be used to see how accurately the antenna must be aimed. The simplest and easiest improvement is to use an higher-gain omni-directional antenna (6-12 dBi), thereby avoiding the need to aim the antenna. Such an antenna works by concentrating energy/sensitivity in the horizontal direction that would otherwise be wasted vertically (up or down). Antenna Elevation Higher antenna locations tend to have less interference (e.g., from other boats) than lower locations, so in general it's a good idea to locate the antenna as high as is practical. On a sailboat, the ideal location is at the top of the mast (with an outdoor wireless Ethernet client bridge located as close to the antenna as possible). Permanent Installation Wired versus Wireless Clients Controlling Wireless Ethernet Bridges Power Relaying and Mesh Networks External Links